Twin Pregnancy in Brazil: A Profile Analysis Exploring Population Information from the National Birth E-Registry on Live Births

Abstract

Birth records as SINASC (Brazilian Live Birth Information System) are highlighted in uncommon conditions such as twin pregnancy whose prevalence rarely exceeds 2 to 3% of the total number of births. The objective of this study was to assess the prevalence of twin pregnancies in Brazil and their maternal and perinatal characteristics using data from the national birth e-Registry. All births in Brazil from 2011 to 2014 were assessed. Prevalence of twin pregnancies per region was assessed and correlated with the Human Development Index (HDI). Sociodemographic and obstetric factors and main perinatal outcomes were assessed for the first and second twin, in comparison to singletons, and the second twin compared to the first twin, with PR and 95%CI. A multiple logistic regression analysis was conducted to identify factors independently associated with a low 5-minute Apgar score in twin pregnancies. Twin pregnancy occurred in 1.13% in Brazil, with a higher prevalence in regions with a higher HDI. It was associated with a complete higher level of education (22.9% versus 16.3% for singles) and maternal age > 35 years (17.5% versus 11.4% for singles). Preterm birth <32 weeks (prevalence ratio-PR 12.13 [11.93 – 12.33]), low birth weight (PR 17.8 [17.6-18.0] for the first and PR 20.1 [19.8-20.3] for the second twin), and low Apgar score (PR 2.9 [2.8-3.0] for the first and PR 2.7 [2.6-2.8] for the second twin) were the most important perinatal outcomes associated with twin pregnancies. A 5-minute Apgar score < 7 among twins was associated with inadequate prenatal care, extreme preterm birth, vaginal delivery, intrapartum cesarean, and combined delivery. Twin pregnancy in Brazil is associated with worse perinatal outcomes, especially for the second twin.